1. Field of the Invention
The present invention relates to an austenitic iron-base alloy and thermal-mechanical process which provides a hydrogen environment embrittlement resistant alloy having enhanced mechanical properties for elevated temperature service in hydrogen fueled rocket engine environments.
2. Description of Related Art
It is well known that alloys of iron and nickel can be produced to provide alloys having high strength at elevated temperatures under severe environment conditions. These alloys have, however, been shown to be susceptible in many cases to hydrogen environment embrittlement. Several iron-nickel-base superalloys have similarly been shown to be resistant to hydrogen environment embrittlement but do not possess the mechanical properties required for rocket propulsion application and especially for rocket engine turbine disk usage. The following references disclose alloys of this type.
U.S. Pat. No. 3,199,978 discloses a high-strength precipitation hardening austenitic alloy of iron, nickel and chromium containing at least one precipitation hardening component from the group consisting of titanium, and/or aluminum, incorporating critical amounts of boron therein.
U.S. Pat. No. 3,065,068 describes alloys encompassing a precipitation hardenable iron-base austenitic alloy containing up to 0.02% carbon, from 1.0% to 3.0% manganese, up to 1.5% silicon, from about 10% to about 22% chromium, from about 15% nickel, from about 0.25% to about 2% molybdenum, from about 0.5% to about 4.5% titanium, up to about 1.0% aluminum, from about 0.1% to about 1.5% vanadium, from about 0.1% to about 0.8% boron and the balance iron with incidental impurities.
However, none of the alloys disclosed in the aforementioned U.S. patents are formulated such that they exhibit acceptable high hydrogen environment embrittlement resistance for use as rocket engine turbine disks.
Accordingly, it is an object of the present invention to provide a heat resistant alloy exhibiting high hydrogen environment embrittlement resistant.
Another object of the present invention resides in a precipitation hardening, high-strength alloy, and a method of producing same.
It is a further object of the present invention to provide a precipitation hardened article of manufacture in the form of forgings and the like and specifically in the form of turbine disks.
These and other objects of the present invention will become apparent from a reading of the detailed description of the invention and attendant claims.